The Properties of Cement Paste Incorporating Multi Wall Carbon Nanotube Solution Prepared through Bead Mill and High-Pressure Homogenizer Process with Polycarboxylate Ester

Abstract

Carbon nanotube (CNT) has been successfully used for production of cementitious composites due to its excellent mechanical properties. In most of the existing literatures, the dispersion of CNT was mostly achieved using either ultrasonic water bath or tip sonicator that is known to provide relatively small amount of energy. In this work, the high energy dispersion processes, bead mill and high-pressure homogenizer, which have been applied for other industrial purposes, were applied to prepare multi wall carbon nanotube (MWCNT) solution with polycarboxylate ester (PCE) as a dispersing agent. The MWCNT solution was used for preparation of cement paste specimens. Ultrasonic tip sonication, a conventional lab-scale dispersion process, was also used for comparison purposes. According to the experimental results, PCE in MWCNT solution behaved as an air-entraining high-range water reducer for cement paste, causing increase in porosity, retardation in hydration, and reduction in undisturbed yield stress. Such effect was more significantly observed from the cases with bead mill and high-pressure homogenizer than ultrasonic tip sonication. The 28-day compressive strength increased by the addition of MWCNT, showing the maximum efficiency at 0.05% MWCNT content. The viscosity of cement paste increased as the amount of MWCNT increased, but flexural strength generally decreased as MWCNT was incorporated.